1. Field of the Invention
This invention relates to thermally-responsive record material. It more particularly relates to such record material in the form of sheets coated with color-forming systems comprising chromogenic material (electron-donating dye precursors) and acidic (electron accepting) color developer material. The invention particularly concerns thermally imaging record materials imaged with sensitive information such as prescriptions, prescription container labels, government forms, tax returns, banking statements, credit card receipts, account information and the like, where privacy or security of the information is desirable.
2. Description of the Related Art
Thermally-responsive record material systems are well known in the art and are described in many patents, for example, U.S. Pat. Nos. 3,539,375; 3,674,535; 3,746,675; 4,151,748; 4,181,771; 4,246,318; 4,470,057 which are incorporated herein by reference. In these systems, basic chromogenic material and acidic color developer material are contained in a coating on a substrate which, when heated to a suitable temperature, melt or soften to permit said materials to react, thereby producing a colored mark.
Thermally-responsive record materials are typically imaged by use of a thermal print head that is moved across the sheet (serial type) or against which the sheet is moved. The thermal printhead can span the width of the sheet (line type). The thermal printhead typically has resistive heating elements. A microprocessor is used to selectively heat the individual heating elements to produce the desired image. Typically the finer the heat elements, the less power is required to produce dots that make up the image. The finer the dots and concentration of dots per unit area, the higher is the resolution.
Thermally-responsive record material systems due to their ease of use, low cost, high resolution, and simple operation have gained acceptance supplanting dot matrix printing in many applications.
With increasing concerns relating to information security, prevention of identity theft, and protection of personal privacy, a variety of techniques have been adopted to preserve the confidentiality of printed information. These techniques include shredding, burning, and other means of information destruction. With passage of ever more stringent privacy obligations such as patients rights bills, and other legislation, such as HIPPA requirements in the U.S., there is an increasing need to control private information to maintain confidentiality, reduce liability exposure, reduce risk of administrative agency imposed fines for non-compliance and prevent careless or inadvertent disclosure of private information.
A need exists in some circumstances for rapid destruction of private or sensitive information in bulk. Techniques such as shredding have the drawback of noise, susceptibility to jamming, or possibility of reassembly of information by a determined party. Techniques relying on burning, convection heating, or heating elements are undesirable in many office environments due to safety concerns associated with hot surfaces, fumes, and cleanliness issues in having to deal with ash.
It is an object of the present invention to teach a novel thermal recording system suitable for office environments which when imaged with personal information can be rapidly obscured in bulk without burning or use of devices characterized by fumes or hot surfaces.